CN111815909A

CN111815909A - Wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning

Info

Publication number: CN111815909A
Application number: CN202010692758.1A
Authority: CN
Inventors: 冯凯
Original assignee: Jiangsu Luofeng Intelligent Security Co ltd
Current assignee: Jiangsu Luofeng Intelligent Security Co ltd
Priority date: 2020-07-17
Filing date: 2020-07-17
Publication date: 2020-10-23

Abstract

A wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning is characterized in that a plurality of UWB sensing devices are distributed on a mountain body according to a honeycomb networking mode, and the center of each honeycomb is provided with one UWB sensing device; the UWB sensing device is internally provided with a UWB wireless transceiving module, a core processor, a storage battery pack, an infrasonic wave sensor, a gyroscope, an accelerometer, a geomagnetic sensor, a soil moisture sensor and a vibration sensor; the core processor is respectively connected with the UWB wireless transceiver module, the storage battery pack, the infrasonic wave sensor, the gyroscope, the accelerometer, the geomagnetic sensor, the soil moisture sensor and the vibration sensor; an outdoor relay network is formed among the UWB sensing devices and is connected with a convergence point through the outdoor relay network, and the convergence point is connected with a server; the server is connected with the monitoring platform through a network. The system can monitor the accurate coordinates of the UWB sensing device in each grid point and can track the displacement and angle change of local mountains of the grid in real time when the mountains move.

Description

Wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning

Technical Field

The invention belongs to the technical field of landslide monitoring, and particularly relates to a landslide collapse debris flow monitoring system based on a UWB sensing positioning wireless ad hoc network.

Background

At present, most of early warning and monitoring for landslide collapse and debris flow are sensors arranged by dotted lines, such as slope surface displacement sensing or deep level displacement sensing. Some monitoring points are in places where disasters happen once, and the original high-level places are not necessarily places where disasters happen again because geological stress is released and changed, so that landslide collapse and debris flow early warning by a traditional means become a probability event of landslide early warning.

Factors influencing the slope stability are many, such as landform, geology, weathering degree, vegetation, underground water level and the like, which piece of a mountain body can not be determined to cause a problem, only one face of the mountain body with safety threat is controlled, the slope surface of the whole mountain body threat section is gridded, the characteristics of displacement, inclination, vibration, sound wave and the like of each gridded slope body are measured according to a grid distribution sensor, and then the real full-probability early warning function can be realized only by judging whether mountain body landslide and collapse can occur or not and mud-rock flow according to geological conditions, meteorological conditions, soil water or underground water conditions and the like.

At present, early warning and monitoring of landslide collapse and debris flow (ground disaster) have certain difficulty, and most monitoring places are sensors arranged by dotted lines instead of surfaces, such as slope surface displacement sensing or deep layer displacement sensing. Some monitoring points are sites where disasters happen once, and because the geological stress of the sites is released and changed, the monitoring points are not necessarily sites where disasters happen again, so that the traditional method of arranging sensors by point lines becomes a probability event for early warning of landslide and debris flow. The real full-probability early warning function can be realized only by controlling a section of a mountain with safety threat, gridding the slope surface of the whole mountain threatening section, distributing a plurality of sensors, measuring the characteristics of displacement, inclination, vibration, sound wave and the like of each gridded slope, and judging whether landslide collapse and debris flow can occur or not according to geological conditions, meteorological conditions, soil water or underground water conditions and the like.

If the displacement of the slope body or the collapse of the rock body or the soil body needs to be known, the system needs to know the coordinate position, the posture, the motion direction and the like of each sensor. It is also possible to measure such things as the direction of infrasonic waves generated by geological disasters, the ground sound of the surrounding soil, the moisture content of the surrounding soil, and so on. Therefore, whether landslide is generated or not can be effectively judged, and whether debris flow can be formed or not can be predicted by combining a rain gauge.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a wireless ad hoc network landslide and collapse debris flow monitoring system based on UWB sensing positioning, which can monitor the accurate coordinates of a UWB sensing device in each grid point, track the displacement and angle change conditions of local mountains of the grid in real time when the mountains move, and gather monitoring data to a monitoring platform; the system can also effectively save energy consumption; and timely early warning action can be conveniently realized.

In order to achieve the aim, the invention provides a wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning, which comprises a plurality of UWB sensing devices, a convergent point, a server and a monitoring platform, wherein the UWB sensing devices are connected with the monitoring platform through a wireless network;

the UWB sensing device is internally provided with a UWB wireless transceiving module, a core processor, a storage battery pack, an infrasonic wave sensor, a gyroscope, an accelerometer, a geomagnetic sensor, a soil moisture sensor and a vibration sensor;

the UWB wireless transceiving module is used for realizing the interactive connection between the UWB sensing devices so as to form an outdoor relay network between the UWB sensing devices and ensure that the UWB sensing devices are in communication connection with a convergent point through the outdoor relay network; the system comprises a core processor, a plurality of sensors and a plurality of sensors, wherein the core processor is used for controlling the core processor to transmit electric pulse signals in a timing mode and sending the received electric pulse signals of the adjacent sensors to the core processor so as to facilitate positioning and clock synchronization; the core processor is used for carrying out clock synchronization according to the received electric pulse signal;

the UWB sensing devices are distributed on a mountain according to a cellular networking mode, wherein the center of each cell is provided with one UWB sensing device; a plurality of UWB sensing devices close to the convergent point are all arranged on the stable base, and the absolute coordinates of the UWB sensing devices are obtained through the field measurement of a surveying instrument; the UWB sensing device at the upper stage selects at least more than three adjacent UWB sensing devices around the UWB sensing device as UWB positioning reference base stations to perform self positioning during positioning, the UWB sensing device after completing self positioning is also used as a UWB positioning reference base station to be determined at the next stage, and the sum of the relative coordinate of the UWB positioning reference base station to be determined at the next stage and the absolute coordinate of the UWB positioning reference base station to be determined at the upper stage is the absolute coordinate of the UWB positioning reference base station to be determined at the next stage;

the storage battery pack is used for supplying electricity to each part;

the infrasonic wave sensor is used for acquiring infrasonic wave signals generated by rock fracture and friction when the geological landslide is in a face of sliding and the infrasonic wave signals generated by debris flow and transmitting the acquired infrasonic wave signals to the core processor in real time; the core processor performs positioning measurement on geological disaster alternating sound waves of a geological disaster infrasound source by combining infrasound signals of a plurality of adjacent sensors according to the received infrasound signals, and sends positioning measurement results to the server through an outdoor relay network and a convergence point;

the gyroscope and the accelerometer form an inertial measurement unit for acquiring a self inclination angle change signal and an acceleration signal in the movement process of the UWB sensing device and transmitting the self inclination angle change signal and the acceleration signal to the core processor in real time; the core processor is used for processing the received self inclination angle change signal and the received acceleration signal and obtaining the movement speed and the movement distance of the soil at the position;

the geomagnetic sensor is used for acquiring signals of an installation direction and an included angle between the UWB sensing device and the geomagnetic and sending the signals of the installation direction and the included angle between the geomagnetic to the core processor in real time; the core processor is used for processing the received installation direction and geomagnetic included angle signals and obtaining the slope collapse amount and the slope sliding direction of the position where the core processor is located;

the soil moisture sensor is used for acquiring a soil moisture content signal of the position where the UWB sensing device is located and sending the soil moisture content signal to the core processor in real time; the core processor is used for processing the soil moisture content signal and obtaining the change condition of the anti-shearing force of the soil at the position due to water infiltration;

the vibration sensor is used for acquiring vibration signals generated by extrusion friction of soil around the UWB sensing device and sending the vibration signals to the core processor in real time; the core processor is used for processing the received vibration signal to obtain a vibration strength value and controlling the storage battery pack to supply power to all power utilization components when the vibration strength value is larger than a preset threshold value;

the convergent point is used for collecting data collected by all the UWB sensing devices through an outdoor relay network and sending the data to the server;

the server is in interactive communication with the monitoring platform through a network, is used for sending the received data to the monitoring platform in real time, and is used for receiving and executing instructions sent by the monitoring platform;

the monitoring platform displays the received data in real time and is used for controlling the alarm module to carry out alarm reminding on the side of the monitoring center when abnormal conditions occur.

Preferably, the core processor is a low-power ARM single chip microcomputer; the infrasonic wave sensor is a capacitance infrasonic wave sensor.

Further, in order to ensure effective communication connection, more than two UWB sensing devices are always used as relay nodes in each safe and effective communication distance in the cellular networking. Preferably, the server is connected with the monitoring platform through the internet.

In the invention, a plurality of UWB sensing devices carry out effective coverage and redundant configuration by using a honeycomb principle, so that when one or a plurality of UWB sensing devices are buried or destroyed by debris flow or landslide, the rest UWB sensing devices can still provide positioning reference and communication route, and the rest sensors can obtain an optimal transmission path by themselves, thereby ensuring effective monitoring. When the surface layer of the gridded slope body moves to form a landslide or collapse, the silt and stone and water act to form a debris flow, no matter which geological disaster occurs, the surface soil moves or creeps, soil displacement can extrude the silt and stone around the UWB sensing device, a gravel vibration signal is collected, and the core processor controls the storage battery pack to supply power to all power utilization parts when the vibration strength value is greater than a preset threshold value, so that the aim of saving energy consumption can be achieved; the gyroscope and the acceleration can facilitate obtaining the movement speed and the movement distance of the soil at the position; the infrasonic wave sensor can be convenient for a UWB sensing device to quickly and effectively position a geological disaster infrasonic source by utilizing a triangulation principle; the soil moisture sensing can be used for conveniently monitoring the change condition of the anti-shearing force of the soil at the position due to water infiltration; therefore, the UWB sensing device can effectively monitor geological disaster points, and finally can collect the soil motion conditions of each grid in a gathering way and send the collected soil motion conditions to the server through the gathering points. The server sends to the control flat bar through the network, and then the control platform can carry out unusual warning according to the data received to can send alarm information to central person on duty, the person on duty of server side of being convenient for direct notice village promptly withdraw or the traffic operation maintenance carries out traffic detour control, also can be convenient for monitor command center carry out geological disasters analysis decision-making early warning.

Drawings

Fig. 1 is a schematic block diagram of the present invention.

FIG. 2 is a block diagram of the communication between a UWB sensing device and a server in accordance with the present invention;

FIG. 3 is a topology of a cellular networking of UWB sensing devices of the present invention;

fig. 4 is a schematic diagram of the calculation of three-dimensional coordinates by the UWB sensing device in the present invention.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1 to 3, the invention provides a wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning, which comprises a plurality of UWB sensing devices, a convergent point, a server and a monitoring platform;

the UWB sensing devices are distributed on a mountain according to a cellular networking mode, the center of each cell is provided with one UWB sensing device, and effective coverage and redundancy configuration are carried out by using a cellular principle as much as possible during arrangement, so that when one or more UWB sensing devices are buried by debris flow or landslide, the rest UWB sensing devices can still provide positioning reference and communication routes. A plurality of UWB sensing devices close to the convergent point are all arranged on a stable base, and the absolute coordinates (geocentric coordinate system) of the UWB sensing devices are obtained through field measurement of a surveying instrument; and the UWB sensing device of the previous stage selects at least more than three adjacent UWB sensing devices around the UWB sensing device as UWB positioning reference base stations to carry out self positioning during positioning, the UWB sensing device after completing self positioning is also used as a UWB positioning reference base station to be determined of the next stage, the sum of the relative coordinate of the UWB positioning reference base station to be determined of the next stage and the absolute coordinate of the UWB positioning reference base station to be determined of the previous stage is the absolute coordinate of the UWB positioning reference base station to be determined of the next stage, and the absolute coordinate of the UWB positioning reference base stations to be determined stage by stage can be obtained by sequentially extending the above steps.

The storage battery pack is used for supplying electricity to each part;

the infrasonic wave sensor is used for acquiring infrasonic wave signals generated by rock fracture and friction when the geological landslide is in a face of sliding and the infrasonic wave signals generated by debris flow and transmitting the acquired infrasonic wave signals to the core processor in real time; the core processor performs positioning measurement on geological disaster alternating sound waves of a geological disaster infrasound source by combining infrasound signals of a plurality of adjacent sensors according to the received infrasound signals, and sends positioning measurement results to the server through an outdoor relay network and a convergence point; because the infrasonic wave can be diffracted for a long distance, a plurality of positioned UWB sensing devices can receive infrasonic wave signals, accurate infrasonic wave sound sources are obtained through triangulation and filtering, and the infrasonic wave sound sources can also give an early warning to an earthquake to a certain extent.

the convergent point is used for collecting data collected by all the UWB sensing devices through an outdoor relay network (automatic routing) and sending the data to a server;

Preferably, the core processor is an ARM single chip microcomputer with low power consumption; the infrasonic wave sensor is a capacitance infrasonic wave sensor.

Further, in order to ensure effective communication connection, more than two UWB sensing devices are always used as relay nodes in each safe and effective communication distance in the cellular networking. Therefore, redundant links can be formed conveniently, and the smoothness and the reliability of communication can be guaranteed more effectively.

Preferably, the server is connected with the monitoring platform through the internet.

Preferably, the monitoring platform displays the controlled area by using a GIS platform, and preferably, a 3D scene can be displayed, so that the geological disaster which is about to occur or is happening in which area can be accurately known through a virtual reality technology. When the monitoring platform finds abnormal conditions, the monitoring platform carries out alarm prompt through the GIS platform, can directly send the abnormal conditions to a central attendant through a short message mode, and certainly can inform the central attendant through voice equipment so as to timely process alarm problems. Usually, the center can take county areas as units, each county area simultaneously displays the geological metamorphosis condition of a controlled slope of a plurality of villages and towns, roads or watersheds, when red early warning is displayed on a GIS platform, the counties, the towns and the villages can be expanded layer by layer, all UWB sensing device position information and alarm information of the last slope of the counties, the towns and the villages are displayed, and when the monitored quantity exceeds a threshold value through a weighting algorithm, slope grid area early warning or sensor installation point early warning is directly displayed. When the central on-duty personnel receive the early warning information, the central on-duty personnel can issue early warning information to WeChat, short message and village wireless early warning broadcast of local people after decision making. And can also be linked with a radio station to be played in a rolling way in a television and a radio.

Preferably, the UWB sensing devices perform accurate positioning by using the TDOA principle, each UWB sensing device performs time difference determination and outdoor relay positioning with not less than three UWB sensing devices near a convergence point, and obtains absolute coordinates of each sensor by measuring relative positions and then performing cumulative translation on the absolute coordinates (geocentric coordinate system). Specifically, the core processor performs calculation of three-dimensional coordinate information by using a TDoA (time difference of arrival) algorithm, and TDoA (time difference of arrival) positioning is a method for performing calculation by using a time difference. Accurate absolute time is relatively difficult to measure, the distance difference from the signal to each positioning base station is calculated by comparing the time difference from the signal to each UWB positioning base station, and a hyperbola taking the positioning base station as a focus and the distance difference as a long axis can be made, and the intersection point of the three groups of hyperbolas is the position of the positioning label. As shown in fig. 4, the coordinates of the UWB positioning base station are R1(x1, y1), R2(x2, y2), R3(x3, y3), and R4(x4, y4), the positions of the base stations R1, R2, R3, and R4 are fixed and known at the time of installation and deployment, and the coordinates of the positioning tag are Ro (xo, yo). The propagation speed of the pulse signal is constant v 3 x 10 x 8 m/s, and assuming that the time when the pulse signal reaches base stations R1, R2, R3 and R4 from tag O is t1, t2, t3 and t4, the distance difference between the signal transmitted by location tag Ro and the two base stations is constant with (R1, R4), (R2, R4) and (R3 and R4) as the focal point, 3 sets of hyperbolas can be obtained, and the intersection point of the hyperbolas is the coordinate of location tag O. The system of equations for solving the coordinates (xo, yo) is shown as follows:

unlike ToF, TDoA determines the location of a mobile station by detecting the time difference between the arrival of signals at two base stations, rather than the absolute time of arrival, thereby reducing the system's requirement for time synchronization. The TDoA algorithm is an improvement on the ToF algorithm, and compared with the ToF algorithm, a special time stamp does not need to be added, so that the positioning precision is improved. And finally, eliminating noise and phase jitter through Kalman filtering to improve the ranging and positioning precision.

The communication carrier used in the current wireless communication technology is a continuous radio wave, the frequency and power of the carrier vary within a certain range, and information is transmitted by using the change in the state of the carrier. Whereas UWB technology does not use a carrier wave, it transmits data signals by sending narrow pulses of non-sinusoidal waves in the nanosecond range. The transmitter in a UWB system directly excites the antenna with small pulses without the up-conversion required by conventional transceivers, thereby eliminating the need for utility amplifiers and mixers. UWB systems allow the use of very inexpensive wideband transmitters. Meanwhile, at a receiving end, a receiver of the UWB system is different from a traditional receiver, and intermediate frequency processing is not needed, so that the UWB system structure is simpler to realize. The data transmission rate of the civil commodity can reach 500Mbit/s, and the UWB technology is an ideal modulation technology for realizing personal communication and a wireless local area network. UWB technology trades a very wide frequency bandwidth for high-speed data transmission and shares the frequency bands used by other wireless technologies, not just the already crowded frequency resources. The method can realize data transmission with long distance, low interception rate, low detection rate, high safety and high speed by using huge spread spectrum gain. The UWB system uses intermittent pulses to transmit data, the pulse duration is short, generally ranges from 0.20 ns to 1.5ns, the duty ratio is low, the power consumption of the system is low, and the power consumption of the system is only hundreds of microwatts to dozens of milliwatts during high-speed communication.

The UWB wireless transceiver module is matched with a communication protocol and used for data mutual relay routing between UWB sensing devices; a radio frequency transmitting part of a UWB wireless transceiving module of each UWB sensing device is provided with a predistortion compensation mechanism for compensating frequency spectrum high-frequency loss caused by outdoor long-distance transmission, and a receiving part adopts Kalman filtering to reduce noise and clock jitter influence. Each UWB sensing device can exchange data with an adjacent UWB sensing device through a UWB wireless transceiving module, so that the system can conveniently diffuse according to the TDOA principle through a convergent point time stamping and perform time difference compensation to serve as standard time service, and other UWB sensing devices calculate time difference according to the same principle to perform diffusion, thereby ensuring the synchronization of global clocks; because every UWB sensing device has all passed through standard time service, so utilize the triangulation theory can carry out the positioning measurement to a geological disaster secondary sound source through a plurality of UWB sensing devices, and can conveniently gather the motion of secondary sound source to the convergent point through the network deployment in real time and on the monitoring platform in the surveillance center again.

The UWB wireless transceiver module transmits and receives UWB wireless signals through the omnidirectional antenna connected with the UWB wireless transceiver module, and the signal transmitting part of the UWB wireless transceiver module is provided with the preprocessing module, so that the high-frequency part can be strengthened, and the frequency band part which generates interference on the frequency spectrum of other equipment is cut off. The received signal part has filter correcting part and compensating part to ensure the quality and distance of UWB signal transmission. In order to reduce the influence of an ultra wideband system (UWB) and other wireless communication systems, it is often necessary to use a waveform design method or a filter to set a notch on a frequency band in which other wireless communication systems operate, which causes waveform distortion and time delay of an impulse UWB signal, and makes it difficult to meet the requirements of subsequent signal processing (such as RAKE reception). And the characteristics of UWB signals and channels are utilized to carry out filter compensation on the frequency components at the notch position of the receiving end and restore the frequency components into standard UWB pulses, thereby maintaining the distance resolution capability and multi-path resolution capability of the pulse UWB and meeting the requirements of subsequent signal processing. In addition, in the process of propagation, the attenuation of high frequency and low frequency is more, when the receiver is reached, the waveform is seriously deformed, the low frequency part of the pulse can be attenuated through a programmable filter through pre-distortion treatment to increase the high frequency part, and when the receiver is to be received, the waveform is corrected back through path attenuation.

As a physical layer technology of a communication system, the UWB technology has a natural security performance. Since UWB signals generally spread signal energy over an extremely wide frequency band, UWB signals correspond to white noise signals for general communication systems, and in most cases, the power spectral density of UWB signals is lower than that of natural electronic noise, and it is very difficult to detect impulse signals from electronic noise. After pseudo-randomization of the pulse parameters using encoding, the detection of the pulse will be more difficult. Since ultra-wideband radios transmit monocycle pulses of extremely short duration and extremely low duty cycle, the multipath signals are separable in time. A large number of experiments show that the fading of the ultra-wideband radio signal is at most less than 5dB in the multipath environment with the conventional radio signal multipath fading depth of 10-30 dB.

The impulse has high positioning accuracy. With UWB technology, it is easy to integrate positioning with communication, which is difficult to do with conventional radios. UWB technology has a very strong penetration capability and can perform accurate positioning indoors and underground, whereas GPS (global positioning system) can only work within the visible range of GPS positioning satellites. Unlike GPS, which provides an absolute geographic location, an ultra-wideband radio locator can give a relative position with a positioning accuracy up to centimeter level, and in addition, an ultra-wideband radio locator is cheaper in price, whereas GPS requires stationary measurements of a reference station to reach centimeter level.

In terms of engineering implementation, the UWB technology is much simpler than other wireless technologies and can be realized in a full digitalization mode. It only needs to generate and modulate pulses in a mathematical way, and the circuits needed to implement the above process can be integrated on one chip, and the cost of the device is very low.

Claims

1. A wireless ad hoc network landslide collapse debris flow monitoring system based on UWB sensing positioning is characterized by comprising a plurality of UWB sensing devices, a gathering point, a server and a monitoring platform;

the storage battery pack is used for supplying electricity to each part;

2. The UWB-sensing-based positioning wireless ad hoc network landslide and collapse debris flow monitoring system is characterized in that the core processor is an ARM single chip microcomputer; the infrasonic wave sensor is a capacitance infrasonic wave sensor.

3. The landslide and collapse debris flow monitoring system based on UWB sensing positioning wireless ad hoc network according to claim 1 or 2, characterized in that, in cellular networking, there are always more than two UWB sensing devices as relay nodes within each safe and effective communication distance.

4. The UWB-sensing-based positioning wireless ad hoc network landslide and collapse debris flow monitoring system is characterized in that the server is connected with the monitoring platform through the Internet.